1. Field of the Invention
The present invention relates to a wireless tag detection apparatus which detects a desired wireless tag from wireless tags attached to a number of articles and a method of controlling the wireless tag detection apparatus.
2. Description of the Related Art
A wireless communication apparatus comprising an antenna and capable of reading data from a memory included in each wireless tag and writing data to the memory by performing wireless communications with wireless tags present in the communication range of the antenna using radio waves has been developed and become commercially practical. In a memory of each wireless tag, a unique ID, the so-called tag identification information is stored. By reading the tag identification information, the wireless tags can be specified individually. Such wireless tags are called Radio Frequency Identification (RFID). Further, the wireless communication apparatus is called an RFID reader/writer.
By installing the so-called RFID system formed of such a wireless communication apparatus and wireless tags in a store which sells a number of commodities or a library which stores a number of books and attaching a wireless tag to each article, management of each article becomes easy.
An example of the RFID system is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2007-323423, in which an RFID reader receives a signal transmitted from a wireless tag, and determines whether the wireless tag is present in a predetermined area according to the power value of the reception signal. Another example is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2005-107792, in which the strength of a radio wave transmitted from a reader/writer and received by a wireless tag is detected by the wireless tag, and the detected data is transmitted from the wireless tag to the reader writer.
In a store which sells a number of commodities, there is a case where only one specific commodity needs to be selected from among a number of commodities displayed in the store or from among a number of commodities stored in a number of boxes as stock, when a request for purchase is made by a customer or when the commodity needs to be returned to the head office or the wholesaler, for example. Similarly, in a library which stores a number of books, there is a case where only one specific book needs to be selected from among a number of books, when a request for reading is made by a user or at the time of arrangement of the books.
In this case, even if a wireless tag is attached to each article, it is difficult to efficiently find one specific article with the above-described RFID system which determines existence of the wireless tag in a predetermined area and detects strength of a radio wave received by the wireless tag.